Fix getChallengeFeed "multiple paginated queries" error

Replace .collect() calls with bounded .take() reads inside the paginated
getChallengeFeed query. Convex only allows a single paginated query per
function execution; .collect() on larger result sets can internally trigger
paginated reads, conflicting with the explicit .paginate() call on the
activities table.

Changes:
- follows query: .collect() → .take(1000)
- likes count per activity: .collect() → .take(500)
- comments count per activity: .collect() → .take(500)

Fixes Sentry #7280439142

https://claude.ai/code/session_01Q598Pr5xHFqAS7PAU1GCNA

Author: claude

packages/backend/queries/activities.ts

@@ -173,7 +173,7 @@ export const getChallengeFeed = query({
       const follows = await ctx.db
         .query("follows")
         .withIndex("followerId", (q) => q.eq("followerId", currentUser._id))
-        .collect();
+        .take(1000);
       followingIds = new Set(follows.map((f) => f.followingId));
 
       if (authDebugEnabled) {
@@ -256,12 +256,12 @@ export const getChallengeFeed = query({
               ctx.db
                 .query("likes")
                 .withIndex("activityId", (q) => q.eq("activityId", activity._id))
-                .collect()
+                .take(500)
                 .then((likes) => likes.length),
               ctx.db
                 .query("comments")
                 .withIndex("activityId", (q) => q.eq("activityId", activity._id))
-                .collect()
+                .take(500)
                 .then((comments) => comments.length),
             ])
           : [0, 0];

tasks/2026-03-01-fix-activity-pagination.md

@@ -0,0 +1,23 @@
+# Fix Activity Feed Pagination Error
+
+**Date:** 2026-03-01
+**Issue:** Sentry error #7280439142 — `getChallengeFeed` throws "multiple paginated queries" error
+
+## Problem
+
+The `getChallengeFeed` query uses Convex's built-in `.paginate()` for the main activity feed, but also calls `.collect()` within the hydration loop to count likes and comments per activity. Convex only allows a single paginated query per function execution; `.collect()` on larger result sets can internally trigger paginated reads, conflicting with the explicit `.paginate()` call.
+
+**Error:** `Uncaught Error: This query or mutation function ran multiple paginated queries. Convex only supports a single paginated query in each function.`
+
+**Stack:** `handler in ../../queries/activities.ts [Line 229]`
+
+## Fix
+
+- [x] Replace `.collect()` calls with bounded `.take()` reads for likes and comments counting inside the paginated hydration loop
+- [x] Replace `.collect()` on the follows query with `.take()` to be defensive
+- [x] Verify typecheck and lint pass
+
+## Notes
+
+- `.take(n)` avoids the internal pagination mechanism that `.collect()` can trigger for larger result sets
+- The limits chosen (1000 for follows, 500 for likes/comments) are generous for real-world usage and stay within Convex's per-function document read limits